This invention relates to lawn mowers and more particularly to hydraulically driven lawn mowers.
One type of hydraulically driven lawn mower, such as that disclosed in U.S. Pat. No. 3,616,869, includes a pair of drive wheels each of which is independently operated by an individual pump coupled to the mower's engine. Each pump includes a control lever for regulating fluid pressure to each motor and the direction fluid flow. In this manner, the drive wheels can be independently rotated at selected forward and reverse speeds whereby the mower may be driven either forwardly or in reverse and may be turned through various angles. Hand levers on the mower are manipulated for moving the control levers into the desired positions. A friction type pivot is disclosed in U.S. Pat. No. 3,616,818 for holding the hand levers in selected forward drive positions.
In walking type lawn mowers, the operator must maintain contact with handgrips at the rear of the mower to facilitate manipulation and control. For this reason, it has been suggested that hand operated control levers for each of the drive wheel pumps be mounted for pivotal movement on the mower's handgrips. This has not been wholly satisfactory, however, because the operator is required to exert hand pressure on the levers in order to maintain the desired speed. This causes fatigue, particularly when the mower is used for long periods, such as in the case of commercial operation. In addition, it is difficult to control manually both pumps so that both wheels are driven at the same forward speed.